1. Field of the Invention
The present invention relates to a transfer apparatus which displays an image recorded in digital form by a digital still camera (DSC), a video camera, a personal computer or the like through a transmission type image display means formed by a liquid crystal display (LCD), and transfers the displayed image onto a photosensitive recording medium, such as an instant photographic film, which develops color by light, resulting in forming an image.
2. Description of the Related Art
Conventionally known examples of a method for transferring (or printing) or recording a digital-recorded image to or on a photosensitive recording medium include an ink jet system using a dot-type printing head, a laser recording system, and a thermal recording system.
A printing system such as the ink jet system has various problems. For example, printing takes more time, ink is likely to cause clogging, and precision printing results in the printed sheet paper being moistened by ink. The laser recording system involves an expensive optical component such as a lens, resulting in high cost performance. Further, the laser recording system and the thermal recording system require considerable power consumption, and are not suited to be carried about.
Thus, generally speaking, the transfer apparatus used in these systems and, in particular, the ones used in the ink jet system have a problem in that the more precise the device, the more complicated the driving mechanism and the control mechanism, and the larger and the more expensive the device, printing taking more time.
In this regard, JP 10-309829 A and JP 11-242298 A disclose transfer apparatus of the type in which a display image is formed on a photosensitive recording medium such as an instant film, using a liquid crystal device, thereby achieving simplification in structure and a low cost.
The electronic printer disclosed in JP 98-309829 A is capable of copying the display screen of a liquid crystal display on a photosensitive medium to produce a hard copy of a quality equal to that of a photograph. However, in this electronic printer, an optical component such as a rod lens array is arranged between a display screen of the liquid crystal display and a photosensitive medium, so that a predetermined distance (total conjugate length) is required between them. In the example shown, a distance of 15.1 mm is required. Further, an optical component is generally expensive.
In the transfer apparatus disclosed in JP 11-242298 A, there is no need to use an expensive optical component such as a lens and/or to secure an appropriate focal length. Thus, as compared with a conventional transfer apparatus, a further reduction can be achieved in terms of size, weight, power consumption, and cost. As shown in FIG. 8, a photosensitive film 400 is closely attached to the display surface of a transmission type liquid crystal display (hereinafter referred to as LCD) 300, and a light source (back light 100) provided on the opposite side of the photosensitive film 400 with respect to the LCD 300 is turned on. That is, a fluorescent lamp 101 is switched on to turn on the back light, so that the image displayed on the LCD 300 is transferred to the photosensitive film 400.
Further, as shown in FIG. 8, the above-mentioned document discloses another embodiment, according to which a lattice 200 is provided between the back light 100 and the LCD 300, so that diffusion or light from the back light 100 is restrained. That is, the light is approximated to parallel rays. Further, by providing a spacer 201 having a rectangular hollow portion between the lattice 200 and the LCD 300, it is possible to prevent the image of the frame of the lattice 200 (the shadow due to the frame) from being taken by the photosensitive film 400, thus improving clarity of the image formed on the photosensitive film 400 to a satisfactory degree from the practical point of view without providing an optical component or maintaining a predesired focal length.
Further, as shown in FIG. 7, the above documentation discloses an example of a transfer apparatus in which thickness of the LCD 300, i.e., the total thicknesses of the following components: a polarizing plate 301 on the display surface side, a glass substrate 302, a liquid crystal layer 303, a glass substrate 304, and a polarizing plate 305 on the back light 100 side is 2.8 mm and in which the image on the screen of the LCD 300 with a dot size of 0.5 mm is transferred to the photosensitive film 400. To prevent diffusion of light from the LCD 300, a 5 mm lattice is provided with a thickness of 10 mm, and a 20 mm spacer 201 is arranged between the lattice 200 and the LCD 300. Further, the LCD 300 and the photosensitive film 400 are closely attached together to effect image transfer without involving blurring (unclarity) of the image.
In this casing, an image displayed with an original dot size of 0.5 mm is transferred with an enlarge dot size of up to 0.67 mm, which is enlarged by approximately 0.09 mm at one side, However, the image obtained is satisfactory on practical.
As described above, in the transfer apparatus disclosed in JP 11-242298 A, image transfer is effected, with the liquid crystal display (LCD) and the photosensitive film being closely attached together, to prevent blurring (unclarity) of the image and to obtain an image satisfactory from the practical point of view. It is to be noted, however, that exposure of the photosensitive film in this arrangement involves the following problems.
First, as shown in FIG. 8, on the outermost surface of the LCD 300, the film-shaped polarizing plate 301 is arranged, closely attaching to the photosensitive film 400. As a result, when the photosensitive film 400 is moved to perform a post-processing, the photosensitive film 400 and the polarizing plate 301 are mutually rubbed thereby flawing the film-shaped polarizing plate 301, and the flaw on the polarizing plate 301 is transferred to the photosensitive film 400. Further, this flaw causes scattering of light, resulting in deterioration of the image quality.
It might be possible for the polarizing plate and the photosensitive film to be closely attached together during exposure and slightly spaced in addition to each other when the photosensitive film is moved. For this purpose, however, it would be necessary to provide, apart from the photosensitive film moving mechanism, a mechanism for effecting close attachment and detachment of the photosensitive film, which is contradictory to the requirement for reduction in cost and size.
Further, generally, a photosensitive film, e.g., an instant film easiest to use, is accommodated in a lightproof casing until it is loaded in a transfer apparatus. Because this lightproof casing is equipped with an opening frame somewhat larger than the film, following procedure is required; that the photosensitive film can be brought into close contact with the polarizing plate.
First, prior to exposure, a signal sheet of photosensitive film is extracted singly from the lightproof casing, and brought into close contact with the polarizing plate surface on the surface of the LCD. In this state, exposure is performed, and, therefore, the photosensitive film is separated from the polarizing plate surface, and moved for a next processing (In the casing of an instant film, a processing liquid tube provided in the film sheet is pushed and broken).
Such a procedure must be repeated for each photosensitive film. In particular, separating the closely attaching photosensitive film to the polarizing plate surface therefrom does not meet the requirements of automation (or mechanization).
Recently, a screen of LCDs have progressed in terms of fine definition, and LCDs with more number of pixels and a smaller dot size are being commercialized. For example, as LCDs using low-temperature polysilicon type TFTS, UXGA (10.4 inches: 1200xc3x971600 pixels), XGA (6.3 and 4 inches; 1024xc3x97768 pixels) are on the market.
An attempt to apply an LCD with such a high-definition screen to the transfer apparatus disclosed in JP 11-242298 A would lead to the following problem. In a casing of UXGA, the dot size of each of the RGB pixels is approximately 0.04 mm on the shorter side. In a transfer apparatus as disclosed in the above-mentioned document, when the dot size is enlarged, it would be impossible to transfer an LCD image of such a minute dot size to a photosensitive film with satisfactory clarity in a state in which the dots of the RGB pixels are clearly distinguishable.
It is an object of the present invention to eliminate the above problems in the conventional art and to provide a transfer apparatus which can realize a substantial reduction in size, weight, power consumption, and cost with a simple structure and which can also be formed as a portable device.
Further, it is another object of the present invention, in addition to the above to provide a transfer apparatus capable of removing scattered light elements from light incident on a transmission-type image display, making this light have only components closer to components of parallel light, and making the light incident normally to the image display, thereby transferring an image (forming an image) with a high definition on a photosensitive recording medium by the light carrying the display image which has passed through the image display, resulting in obtaining a transferred image having a fine definition.
In order to achieve the above objects, the inventors have devoted themselves to researching a transfer apparatus that is capable of obtaining a fine-definition image, practical, and capable of using a transmission-type image display such as a liquid crystal display. As a result of this research and development, in order to prevent blurring (low definition) of the image and obtain the transferred image with fine definition using a simple and practical device construction, the inventors have learned that it is necessary to have a substantially parallel light generating element remove the scattered light elements from the light incident on the image display so that the light has only elements closer to those of parallel light and to make the light incident normal to the image display at a perpendicular angle. In order to achieve this, the inventors found that it was necessary to construct the substantially parallel light generating element constituted by a porous board provided with a plurality of through-holes, and necessary to set the value of the ratio of the thickness of the porous board to the diameter of the through-holes or corresponding diameter within a predetermined range, resulting in completing this invention.
The present invention provides a transfer apparatus having a light source, a substantially parallel light generating element, a transmission-type image display unit and a photosensitive recording medium which are arranged in a series along the traveling direction of light of the light source, for transferring onto the photosensitive recording medium a display image having passed through the transmission-type image display means, wherein the substantially parallel light generating element is formed by a porous board provided a plurality of through-holes, and a thickness of the porous plate is equal to or greater than three times a diameter of each of the through-holes or a calculated diameter corresponding the former diameter.
Preferably, at least the inner surfaces of the through-holes in a surface of the porous board, is a surface having a reflectance of 2% or less.
Preferably, a cross-sectional shape of the porous board is formed in a round or polygonal manner.
Preferably, a size of the image displayed on the image display unit is substantially as same as a size of the image transferred to the photosensitive film.
Preferably, a size of each pixel of the image display unit is equal to or less than 0.2 mm.
Preferably, the image display unit is a liquid crystal display.